Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U. Iowa study adds to understanding of salt-taste

03.07.2003


Saltiness often enhances our enjoyment of certain foods -- think French fries or a Margarita. But salt is an essential nutrient for humans and other animals, and far from being a trivial matter of taste, the ability to detect salt is critical for survival. A University of Iowa study provides insight on how humans and other animals are able to detect salt. The study appears in the July 3 issue of Neuron.



"Given that salt is essential for survival, it is not surprising that animals have developed the ability to detect salt, even at low concentrations. This sense allows them to seek out, and then consume salt," said Michael Welsh, M.D., the Roy J. Carver Biomedical Research Chair in Internal Medicine and Physiology and Biophysics, UI Professor, and Howard Hughes Medical Institute Investigator. "We were interested in identifying the receptors that detect small quantities of salt."

The ability to detect when something is too salty is also important. Consuming very high concentrations of salt could be potentially harmful.


Previous research suggested a role for a specific type of protein in salt-sensing. Lei Liu, Ph.D., UI postdoctoral researcher and lead author of the study, and colleagues turned to the fruit fly (Drosophila melanogaster) to investigate these proteins, known as ion channel proteins.

Fruit flies and humans share the ability to detect salt. Fruit flies also respond to salt in ways that are similar to those seen in humans and other animals. For example, fruit flies are attracted to low salt but are repelled by high salt.

"In humans the taste system is pretty much a puzzle because it is hard to study," Liu said. "But in fruit flies it is very easy to study and you can quickly test ideas. Also, fruit flies are a great genetic model where you can easily screen many different genes to determine what they do and how they interact."

The ion channel genes studied are called pickpocket (ppk). The UI team discovered that two of these ion channel genes are involved in the detection of low salt concentrations. The study also suggests that these genes play some role in detecting high salt concentrations, but it is likely that other pathways also are involved in high salt detection.

The UI team focused on the two pickpocket genes, ppk11 and ppk19, because they found that these genes are expressed in body parts of the flies that are involved in taste-sensing. In the fruit fly larva (young flies) the genes are expressed in a body part known as the terminal organ, which resembles a human taste bud.

Using a series of behavioral experiments, the UI researchers discovered that disrupting the two genes impaired the ability of young flies to detect low salt concentrations.

Normally, young fruit flies prefer water containing low salt concentrations to plain water. However, young flies with disrupted genes were unable to detect low salt. Disrupting either gene also altered how both young and adult flies reacted to high salt concentrations.

"When we disrupt the genes we see defects in behavior," Liu said. "To see if the receptor cell itself is being affected, we measured the action potential (nerve impulse) of the receptor cell in the terminal organ of the mutant larva. The response of the receptor cell to salt is reduced by the mutation."

The UI study also showed that the two genes play a role in the ability of flies to distinguish between different types of salt (sodium chloride and potassium chloride). However, disrupting the genes did not seem to affect the fruit flies’ responses to other tastes.

Understanding salt-sensing mechanisms and identifying two ion-channel proteins that detect low salt in fruit flies may be directly relevant to the salt-sensing system in humans.

Although salt is an essential nutrient, individuals with certain conditions such as high blood pressure or heart failure are often advised to reduced their salt intake. Liu said that identifying the receptors involved in salt detection may eventually aid in the design of salt substitutes, which enhance flavor but do not hurt our health.

In addition to Liu and Welsh, Soren Leonard, Ph.D., David Motto, M.D., Ph.D., Margaret Feller, Margaret Price, Ph.D., and Wayne Johnson, Ph.D., UI professor of physiology and biophysics, also were involved in the study. The work was funded in part by grants from the National Institutes of Health.

University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at http://www.uihealthcare.com.



STORY SOURCE: University of Iowa Health Science Relations, 5135 Westlawn, Iowa City, Iowa 52242-1178

Media Contact Jennifer Brown, 319-335-9917, jennifer-l-brown@uiowa.edu

Jennifer Brown | EurekAlert!
Further information:
http://www.uihealthcare.com

More articles from Life Sciences:

nachricht Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>